The present invention relates to a shift control device for an automatic transmission of a vehicle such as an automobile, and particularly, to a system for shifting a vehicle transmission and for providing improved tactile feel that is synchronized with the shifting operation.
Vehicles equipped with an automatic transmission often include a shift control lever mounted on a console, the dashboard, or the steering column of the vehicle. A vehicle operator may manually move the shift control lever between shift lever positions so as to change the gear position in which the transmission is engaged and thereby actuate the transmission into a desired gear position.
In general, when an operator of a vehicle operates a control mechanism, such as a shift lever, the vehicle operator seeks feedback in order to know how hard or how far to push or pull or turn the lever. In some cases, the feedback is provided visually by a display. Additional feedback may also be provided in the form of tactile feel. When an operator encounters feedback in the form of tactile feel, the operator senses a tendency in the control mechanism toward or away from a particular position of the control actuator (e.g., lever, knob, dial, or wheel). To overcome the tendency, the operator typically must oppose it with an increased level of force.
A shift control lever may employ a leaf spring mechanism within the transmission to help overcome the frictional forces of the shift control lever and the associated linkage system and to aid in completing a shifting operation in the event the operator fails to independently complete the shifting operation. In systems where the frictional forces are excessive, or where excessive play may develop between the shift control lever and the associated linkage system, the shift control lever and its associated linkage system may become misaligned from the transmission. In addition, the imposition of frictional forces at points in the linkage system between the transmission and the shift control lever can result in a loss of tactile feel at the shift control lever.
Accordingly, it is desirable to have a system for shifting a vehicle transmission that provides improved tactile feel to the operator and that can be synchronized with shifting operations within the transmission.